Cheapvega.
My friend was testing dml panels a few years ago with his OBs but we haven't been able to have a get together and listen for a couple of years now, what with one thing and another .
Hopefully this year we will get together for some serious listening.
Many years ago I did use some 15inch drivers without baffles to help fill in the 300 hz and below on my 7ft eps panels.
Large OBs was not really an option in my small room.
Steve.
My friend was testing dml panels a few years ago with his OBs but we haven't been able to have a get together and listen for a couple of years now, what with one thing and another .
Hopefully this year we will get together for some serious listening.
Many years ago I did use some 15inch drivers without baffles to help fill in the 300 hz and below on my 7ft eps panels.
Large OBs was not really an option in my small room.
Steve.
Christian.
I was wondering if you could give your opinion on the sound of the art panel up against the back and side walls.
and the effects on the quality of sound with one edge up against the wall poking strait out and then slowly pivoting the panel back against the wall.
I felt that it sounded pretty good as long as I did not swing them back too close to the wall.
This would hopefully make them ideal for surround speakers as they did not seem to suffer badly from the one edge against the wall?
you might think the think the wall effects the sound too much, but your opinion would be interesting.
Steve.
I was wondering if you could give your opinion on the sound of the art panel up against the back and side walls.
and the effects on the quality of sound with one edge up against the wall poking strait out and then slowly pivoting the panel back against the wall.
I felt that it sounded pretty good as long as I did not swing them back too close to the wall.
This would hopefully make them ideal for surround speakers as they did not seem to suffer badly from the one edge against the wall?
you might think the think the wall effects the sound too much, but your opinion would be interesting.
Steve.
I've seen some completely baffle-less systems with big drivers that seem to have worked well. My main issue is maintaining a similar look with whatever I go with:
The panels will def have to hang lower, but not by much. They might need 90 degree extensions and a little more size as well. But if I could get the panels to extend low enough that I could ditch my sub I would be ecstatic. Though if they could get down well below the sub's HPF max (~150Hz) that would be good enough.
Christian,
I've been looking over your DML material graph and data. I'm curious about this one for the Tectonics DML 100?
How did you infer those numbers?
On the DML500 tech sheet below, on page 2 there is a "Hemispherical Contour Plot" from which I infer an Fc for that panel of about 5 KHz. They also describe it as 378x478 mm Carbon fiber honeycomb, which I assume they mean carbon fiber skins over a honeycomb core (maybe Nomex? But I don't see anything else that would would give me clue. How did you come up with your guesses for stiffness and density?
Thanks,
Eric
https://www.tectonicaudiolabs.com/wp-content/uploads/2019/12/Tectonic_SpecSheets_DML500_FINAL.pdf
Hello Eric
Thank you for your feedback. I took notes of all of that in the attached file (now part of my tech notes)
Christian
Veleric.
I notice on page 2 of the DM 500 link you posted that they too prefer to use multiple microphone measurements , 1349 to be precise , in 5 deg intervals vertical and horizontal and then averaged .
This makes sense to me ,although my method of moving the microphone around the listening position on peak hold does a pretty good job of averaging the response in that area too.
Steve.
I notice on page 2 of the DM 500 link you posted that they too prefer to use multiple microphone measurements , 1349 to be precise , in 5 deg intervals vertical and horizontal and then averaged .
This makes sense to me ,although my method of moving the microphone around the listening position on peak hold does a pretty good job of averaging the response in that area too.
Steve.
Cheapvega.
I made a mp4 recording of my 6x9inch veneer panel to show what happens when you mount a panel flat up to a wall or ceiling, but it seems mp4 does not upload anymore .
I did post the question about upload formats in forum problems but with no answers, so it would seem like no more recordings ?
The response below at least 500hz falls away dramatically when placed flat against The ceiling.
The music I was playing had very strong bass down to 40hz which came through in the centre of the room and with one edge close to the ceiling as in the picture but not flat up against the wall !
Steve.
I made a mp4 recording of my 6x9inch veneer panel to show what happens when you mount a panel flat up to a wall or ceiling, but it seems mp4 does not upload anymore .
I did post the question about upload formats in forum problems but with no answers, so it would seem like no more recordings ?
The response below at least 500hz falls away dramatically when placed flat against The ceiling.
The music I was playing had very strong bass down to 40hz which came through in the centre of the room and with one edge close to the ceiling as in the picture but not flat up against the wall !
Steve.
Attachments
Just made some quick measurements of the panel ,one with the panel edge close to the ceiling as in the photo and one with the exciter side up close to the ceiling.
The microphone was lying on the listening area seat and the panel was about 2.5m in front, but on the ceiling.
The roll off in The top end is more to do with the CD and mic position.
Steve.
The microphone was lying on the listening area seat and the panel was about 2.5m in front, but on the ceiling.
The roll off in The top end is more to do with the CD and mic position.
Steve.
Attachments
I should have mentioned that I was playing a track from the CD on peak hold, that has a lot of low bass .
The dip in response above 100hz reduces the closer you get to the panel.
Steve.
The dip in response above 100hz reduces the closer you get to the panel.
Steve.
I couldn't find where to ask this in the proper forum, so I'll ask it here. I just updated Audacity. Now I can't open my songs to modify them because it says that I need to upgrade FFmpeg. I went to the site they named, and the instructions are so esoteric that I can't figure it out. Anybody else have any luck updating Audacity that can lend me a hand? I was constantly using Audacity and now I can't. Maybe someone could direct me to proper forum to ask this question, too.
About the Audacity problem, I just re-downloaded the release prior to this one, and crisis averted. I don't understand why they can't make the add-ons simpler to add on, instead of the gobbledy-goop way of doing it. Just make an assembled package that you can copy and add on like 99% of ALL other software systems do! I can't be the only person who has this problem.
Jaxboy .
glad you managed to sort out your Audacity .
no doubt I'll have that joy to sort out when I come to update my Audacity 😁
Christian.
I measured my 6x4 inch ply panel that I peeled off of my canvas panel,which is missing one of its plys as it is still stuck on to the canvas .
Sorry about the quality of the photos, hopefully I will get a new phone soon ?
The lines are in 5db steps.
The roll off point at 3m is just below 400hz.
pic 1
30cm
Pic 2
1m
pic 3
3m
Steve
glad you managed to sort out your Audacity .
no doubt I'll have that joy to sort out when I come to update my Audacity 😁
Christian.
I measured my 6x4 inch ply panel that I peeled off of my canvas panel,which is missing one of its plys as it is still stuck on to the canvas .
Sorry about the quality of the photos, hopefully I will get a new phone soon ?
The lines are in 5db steps.
The roll off point at 3m is just below 400hz.
pic 1
30cm
Pic 2
1m
pic 3
3m
Steve
Attachments
Wow that is substantial. I'm embarrassed to admit I only measured my panels off the ceiling once. So it could entirely be the placement.
However, I was looking at some more materials to play with, and I came across this dude's setup:
http://projectgallery.parts-express...-192-watt-diy-dml-panel-speaker-build-bertha/
He is getting really good bass with the panels basically resting on the wall:
https://www.youtube.com/channel/UCTebi_4eyK1xhpWHvAt00Rg
Granted he is also throwing huge watts at the panels, but he's not really EQing beyond some generic bass/treble adjustments on his amp. Power at the source and drivers are relatively cheap. Could plexiglass be the DML holy grail?
Sheets are a little pricey, but if I can get away with a thinner sheet (he used 1/4" thick panels; 1/8" thick panels are half the price) then this could be a nice low cost low effort material with good low end extension. Even if these don't get all the way down to ~40Hz.... again I'd be happy with like ~100Hz. I will try and grab + test some 18x24" and 1 20x32" sheets this week.
Steve,
The update for Audacity doesn't really address any urgent problems, so I wouldn't open that can of worms unless you had been having problems with it. Read the blurb that comes with the update to decide if you want to deal with the hassle of trying to figure out how to decipher how to reload FFmpeg and lame.
The update for Audacity doesn't really address any urgent problems, so I wouldn't open that can of worms unless you had been having problems with it. Read the blurb that comes with the update to decide if you want to deal with the hassle of trying to figure out how to decipher how to reload FFmpeg and lame.
Cheapvega, thanks for the link - these are impressive! Davelang also had great results with plexiglass: https://www.diyaudio.com/community/...s-as-a-full-range-speaker.272576/post-6242579
I've successfully used 1/16" plexiglass panels for my TV sound system with single Thrusters on each panel.
Hello Steve. I don't forget your question, it is my dolist... I am a bit busy by the time being for family reasons. My intention is also to make a feedback about some measurements I made with canvas panel to see how it reacts to a rear wall.
I found this video about canvas panel. Very good to have the basis of the canvas panel construction. I wonder about 2 points in this video : fantastic dml speakers
- the thickness of the ply pad (6mm birch plywood). Not to thick? al least for the efficiency
- the role of the metallic pieces
Eric,
Good question! As there is no notes in the file I did some archaeology in my notebooks and on the net... So I think it is from the available information plus some speculations...
The facts for Tectonic panel are (from spec and video)
- 40x50cm (378mmx478mm) => A = 0.2m²
- 3.5mm thick
- carbon honeycomb
- stiff and light (91dB efficiency?)
- used from 100Hz
Here start the speculations...
There is a standard ratio of 2.5 between F0 and 1st usable frequency. This leads to a "classical" F0 = 40Hz
As F0 = pi/A*(D/µ)^.5, it gives D/µ = 6.5. Then Fc = c²/pi*(µ/D)^.5 = 14.5kHz
The second level of assumption I made (and today I can't find how I come to that...) is µ = 0.4kg/m² so D = 2.6Nm
If I find where how I infer the µ value, I will tell you.
By searching for the justification of those values, I found in a Tectonic video the FR and IR of their panel. Interesting to keep.
Christian
PS : I reattached here the pdf about µ and D measurement with the last figure on white background
Attachments
Steve,
I am not sure to understand how you make your measures... Which track to you use?